<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script>
			//js中定义变量，java非常严谨String,int,long
			var x=10;
			var y=20;
			console.log(x+y)
			
			var a=10,b=20;
			console.log(a*b);
			
			console.log(x);
			var x=100;
			console.log(x);
			console.log(typeof(x));
			
			var x="abc";
			console.log(x);
			console.log(typeof(x))
		</script>
	</head>
	<body>
	</body>
</html>
